Emil passburg



(No Model.)

' 2 Shets-Sheet 1. E'. PASSBURG. VACUUM DRYING APPARATUS.

(No Model.)

' .y y2 Sheds-Sheet 2. vE .JEA'SSBURCT- VACUUM BUYING APPARATUS.

Patented Mar. 3, 1891.

v UNITED STATES PATENT Quince.

EMIL PASSBURG, OF BRESLAU, GERMANY.

VACUUM DRYING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 447,345, dated March 3, 1891.

Application filed June 19, 1888I Serial No. 277.609. (No model.) Patented in Germany April 13,1888, No. 49,905; in France May 12,1888,No. 190,569; in England May 22, 1888,No. 7,555; in Belgium September 16, 1889, No. 87,636, and in Austria- Hungary February 5, 1890, No. 46,1 53 and No. 70,557.

To all whom it may concern.-

Be it known that I, EMIL PASSBURG, a subject of the German Emperor, and a resident of Breslau, in the Empire of Germany, have invented certain new and useful Improvements in Vacuum-Drying Apparatus, (for Which I have obtained Letters Patent in the following countries, namely: in Great Britain, No. 7,555, dated May 22, 1888; in Germany, No. 49,905, dated April 13, 1888; in France, No. 190,569, dated May 12,1888; in Belgium, No.A 87,636, dated September 16, 1889, and in Austria-Hungary, No. 46,153 and No. 70,557, dated February 5, 1890,) of which the following is a specification.

r1his invention relates to apparatus in which matters are dried under the combined induence of heat and diminished atmospheric pressure, hereinafter expressedv as and intended to be understood by the term vacuum." i

The object of this invention is mainly to provide a machine in which the drying cylinder or Chamber has a receiving-chamber of size sufficient to receive the Whole charge to be placed thereon for working at any one time, such receiving-chamber to serve as a hopper for supplying the drying-cylinder, and

provided With means for closing it air-tight and for opening and closing the communication between the chamber and the dryingcylinder, and the said machine also having a like delivery-chamber for receiving and containing the charge delivered from the dryingchamber, said delivery-chamber being likewise adapted to be closed air-tight and provided With means for opening and closing the communication betweenl it and the dryingcylinder, these means of controlling communication being respectively independent of the means for outward closing of the receiving and delivery chambers, so that filling and emptying may proceed Without impairing the vacuum in the drying-cylinder, since the closing of the latter from outer air can thus be at all times absolute as distinguished from those constructions to the same end in which the respective inlets and outlets of the receiving and delivering hoppers are respectively controlled by one connecting mechanisni, the further convenience being also added of the enlargement of space for receiving and emptying due to the undivided nature of the receiving and delivery chambers.

A further object is to construct the receiving-chamber with a portion made cylindrical and fitted with a rotary heated. barrel by which the matters to be dried shall be brought to sufficient state of partial dryness only to avoid their adhering to the Walls 0r heating system in the main drying-cylinder to the detriment of the Working of vthe latter, this rotary barrel being preferably so placed and lmade that the materials to be dried are operated upon by the barrel just previous to their introduction into the drying-cylinder, and are by the same means forwarded into the drying-cylinder.

A further object of the invention is to construct the improved machine so that the place or places of communication of the air-exhaust pipe With the apparatus are so located that the dusty particles'developed or freed in the drying-cylinder as the drying progresses, and drawn along by the current of vapor raised from the material, maybe, when the receiving-chamber is in communication with the thereof, partly in section, online X X, Fig. 1. p

A is the receiving-chamber, provided with lids A', by which it may be closed air-tight; B, the cylindrical extension thereof, in which the material received into the chamber A undergoes a preliminary heating prior to its arriving in the drying-cylinder C. The cylinder Bis heated by or through the rotary hollow barrel S, runnin g axiallythrough then/hole length of the cylinder 13. rl `he barrel S is closed at both endswith covers withhollow cast cones or tubes journaled in stufting-boxesin the end. covers of the cylinder B. On the barrel are outwardly-extended spirally-inclined hollow ridges t t for assistance in forwarding the material along the cylinder. The diameter of the barrel is as large as can be conveniently made in proportion to the cylinder B to magnify the heating-surface and to cause the material to be pressed closely on the heating-surfaces by reason of the narrow space left between the barrel and cylinder B, so that the water is partly pressed out of the wet material and can vaporize more easily on the heating-surfaces, thus increasing' their effeet. The free portion of the chamber A being at or above one end ofthe cylinder B and the outlet of said cylinder being at the other end, said outlet being a pipe passing to the drying-cylinder C, the material is forwarded from the tree portion of the chamber A through the cylinder B by the ridges t t on the barrel S into the drying-cylinder C, where it will arrive already dried to a certain extent, so that it will not adhere to the heating-pipes therein. rlhe cylinder C is surrounded in the known manner by a j acket and contains a pipe system comprising a central rotary heating-pipe b of large diameter, giving the necessary strength to the heating system, and a number of smaller heating-pipes b b l), parallel with the pipe b', all fastened steam-tight in the end walls e. The walls c and the end covers D, vaulted inward, and therefore of greater strength against the interior pressure of steam, are together riveted steam-tight on a V-shaped iron ring C, as shown.

The central tubes D', east on the covers D, rotate in stuffing-boxes in the end-closing covers C of the cylinder C, and are hollow and connected in the known manner with the stationary steam-inlet pipe f and exhaustpipe f, respectively.

Of the covers D, that at which the steam or hot air, dsc., is admitted is provided with a bathe-plate fr, distributing the steam, hot air, dsc., on entering. The other carries a bucketpipe fi, throwing out the condensed water which collects in the lower part of space between the wall e and cover D.

Around the main pipe b are lixed at intervals the divided annular rings or holders r, carrying bars a', to which the plates a are attached, the latter lying parallel with the pipe system and distributing and agitating the material in the cylinder C as the system revolves. Thevapor disengaged in the cylinder C is absorbed by the air-pump E, the pipe E from which leads into the upper part of the cylinder B, so that, the vapors from C having to pass through cylinder B on the way to the pump, the dust and particles carried up with said vapors from C are held back by the damp material which is being carried along by the barrel S in the cylinder B.

F is the exhaust-hopper or delivery-chamber for the dried material, it being closed airtight to the outer air by the door F. It is in communication with the cylinder C by the pipe G, placed at the lowest point of said cylinder and at the end opposite to the inlet-pipe G, by which the material to be dried passes into said cylinder C. The receivingchamber A, with its preliminary drying-cylinder B, can be shut oft hermetically from the lower main drying-cylinder C and the latter from the delivery-chamber F by Valves g and g in the pipes G and G respectively, so as not to interrupt the vacuum in the main drying-cylinder C when filling in A or discharging at F.

J is a hand-valve in the air-pipe E.

E is a branch air-pipe leading from the pipe E to the upper part of the cylinder C. This pipe E is provided with a throttle-valve m, which is only opened when valve J in pipe E is closed; in other words, when the receiving-chamber A is being lilled to allow during that process a passage to the vapor from C direct to air-pump E. Valve J is only closed when A is being filled.

The material may be allowed to iill C to such an extent as to well cover the heatingpipes b and b by their rotary motion. y this means, therefore, more effective heating can be given than in drying apparatus the action of which is dependent in principle upon continuous action and continuous through movement of the material. It is also possible not only to dry materials in this apparatus, but also to bake them, if necessary, after drying for a certain time in a higher temperature, it' desired, or by continued action of the vacuum and temperature employed in drying. Thus malt maybe dried therein at first at about 30 centigrade and in a high vacuum and afterward at a higher temperature.

l claim in vacuum drying apparatus- 1. In a drying-cylinder, a system of heatingpipes comprising, in combination, a central pipe b of large diameter, the parallel outer pipes l; of small diameter, the walls e, carrying the ends of said pipes, the V-rings c, and the domedcovers D thereon,substantially as set forth.

2. The combination of a main drying-cylinder, a rotary system of parallel heatingpipes therein, a receiving-chamber having as a part thereof a preliminary heating-cylinder of comparatively small capacity, and a rotary heating and conveying barrel of comparatively large diameter in said preliminary heating-cylinder, adapted to press and feed the wet material into the main cylinder and to dry the same sufficiently to avoid it adhering to the rotary pipe system therein.

3. The combination of the drying-cylinder C, having al rotary system of heating-pipes therein, the receiving-chamber A, adapted to be closed air-tight, the preliminary heatingcylinder B being a part of said receivingchamber, the delivery-chamber F, adapted to IIO be closed air-tight, the pipes of communioa- In testimony whereof I sign this specification G and G', with hand-Valves g and g tion in the presence of two subscribing Wittherein, the air-exhaust pipes E and E commesses.

municating, respectively, With the cylinders I EMIL PASSBURG. 5 B and C, and. the ValvesJand m in said pipes Witnesses:

E and E, respectively, the whole substan- FERDINAND ENDREs, I

tially as and for the purposes herein set. forth. AUGUST HOFFMANN. 

